Selective isomerization of olefins to alkenes using a mesoporous catalyst

ABSTRACT

A process for selectively making 2-alkenes from a NAO using a mesoporous catalyst that has been surface modified with a Brönsted acid compound. The Brönsted acid compound has a reactive silane connector, an organic linking group, and a Brönsted acid group. The mesoporous catalyst has an average pore diameter in a range of about 12 to about 100 Angstroms and a surface area of between about 400 to about 1400 m 2 /gram.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to mesoporous catalysts used toisomerize normal alpha olefins.

BACKGROUND OF THE INVENTION

Olefins, especially those containing about 6 to about 20 carbon atoms,are important items of commerce. Olefins are used as intermediates inthe manufacture of detergents, synthetic lubricants, lube oil additives,plasticizers, and surfactants. Olefins are also used as monomers, suchas in linear low-density polyethylene, high-density polyethylene,polypropylene, polystyrene, etc. and as intermediates for many othertypes of products. As a consequence, improved methods of making thesecompounds are of value.

Most commercially produced olefins are made by the oligomerization ofethylene, catalyzed by various types of compounds, such as alkylaluminumcompounds, certain nickel-phosphine complexes, and a titanium halidewith a Lewis acid such as diethylaluminum chloride (DEAC). In many ofthese processes, significant amounts of branched and/or internal olefinsand/or diolefins are also produced. Because the location of the doublebond in olefins affects the physical properties of the olefins produced,generally, branched and/or internal olefins and/or diolefins performdifferently from terminal olefins, i.e. normal alpha olefins (NAOs). Theposition of the double bond in the olefins also has a significant impacton the physical properties of derivatives made from the olefins. Forexample, a sulfonate salt prepared from a terminal olefin oftenfunctions as an oil-in-water surfactant, but a sulfonate salt preparedfrom an internal olefin, such as in the middle of the molecule, forms adouble tail surfactant that performs well as a surfactant in invertedwater-in-oil emulsions.

When a terminal olefin is isomerized, the double bond migrates to aninternal position to form a more thermodynamically favored isomer. Undernormal circumstances, the double bond migration will lead to athermodynamic statistical distribution of the double bond at each carbonposition of the molecule chain.

Because thermodynamics control double bond distribution during knownolefin isomerization processes, economically producing an olefin withpredominately 2-alkenes has been difficult, particularly when usingheterogeneous catalysts. Attempts have been made to selectively produce2-alkenes using homogeneous catalysts. Homogeneous catalysts, however,are generally more expensive than heterogeneous catalysts. A need existsfor an economical process to selectively produce 2-alkenes. It would beadvantageous if the process used heterogeneous catalysts.

SUMMARY OF THE INVENTION

In view of the foregoing, the present invention provides processes forselectively isomerizing normal alpha olefins (NAO) to produce 2-alkenesusing a mesoporous catalyst that has had its surface modified with asubstance or composition that contains a Brönsted acid compound. Themesoporous catalyst has mesoporous pore diameters that allow the NAO andproducts of varying sizes to enter and exit the catalyst. The Brönstedacid compound generally has three components, namely a reactive silaneconnector, an organic linking group, and a Brönsted acid group. Thereactive silane connector contains a silicon atom and at least oneleaving group attached to the silicon atom that connects the Brönstedacid compound to a mesoporous silicate. The reactive silane connectorcan be a halosilane group, an alkoxysilane group, or combinationsthereof. The organic linking group can be aromatic group, afluoroaromatic group, an alkylene group, a fluoroalkylene group, apoly(etherfluoroalkyl) group, or combinations thereof. The Brönsted acidgroup can be a sulfonic acid group, a carboxylic acid group, orcombinations thereof.

Once the surface of the mesoporous silicate has been modified, themesoporous catalyst forms and minimally has a general structure asfollows:

MP—O—Si-L-BA

wherein MP is a mesoporous silicate, L is the organic linking group, andBA is the Brönsted acid group. The mesoporous silicate contains silicaand optionally aluminate silicate.

The mesoporous catalyst has an average pore diameter ranging from about12 Angstroms (Å) (1.2 nanometers) to about 100 Å (10 nanometers), asurface area ranging from about 400 m²/g to about 1400 m²/g, and a porevolume ranging from about 0.5 cc/g to about 2.0 cc/g. The properties ofthe mesoporous catalyst do not change substantially between pre- andpost-surface modification of the mesoporous silicate.

The processes described herein can be performed in the presence of anoptional mobile phase acid. The mobile phase acid is not required, butcan be used.

In addition to the processes described herein, the present inventionalso provides the mesoporous catalyst that has been surface modifiedwith the Brönsted acid compound as an embodiment of the presentinvention. The mesoporous catalyst has an average diameter ranging fromabout 12 Å to about 100 Å.

DETAILED DESCRIPTION OF THE INVENTION

A process for selectively making a 2-alkene is provided as an embodimentof the present invention. In this embodiment, a NAO having at least 6carbon atoms is contacted with a mesoporous catalyst. The mesoporouscatalyst has been surface modified with a substance or compositioncomprising a Brönsted acid compound. The NAO is isomerized in a reactorto produce a reactor effluent comprising the 2-alkene. In an aspect, thereactor effluent comprises less than about 8 wt. % olefin dimer and noadded branched olefins other than those contained within the feedstream. The reactor effluent contains at least 35 wt. % 2-alkene. Insome embodiments, the reactor effluent can comprise at least 50 wt. %2-alkene.

The substance containing the Brönsted acid compound generally comprisesa reactive silane connector, an organic linking group, and a Brönstedacid group. Each component of the Brönsted acid compound is describedherein. Each Brönsted acid compound component described herein is anindependent element. The quantity or number of each component present inthe Brönsted acid compound can be independent of the quantity of othercomponents present in the Brönsted acid compound. Other independentproperties that are described herein can be used to further describe theBrönsted acid compound.

Once the surface of the mesoporous silicate has been modified, themesoporous catalyst is formed that minimally has a general structure asfollows:

MP—O—Si-L-BA

wherein MP comprises a mesoporous silicate, L is the organic linkinggroup, and BA is the Brönsted acid group. One skilled in the art willrecognize that the silicon atom in the above structure has twoundesignated valencies. As used herein, the undesignated siliconvalencies can each independently be a MP—O— linkage, a linking grouphaving the Brönsted acid group, any other group attached to the siliconatom from the Brönsted acid compound comprising a reactive silaneconnector (e.g. an organic group, a hydrocarbon group, X, R′O—, or ahydroxy group). The mesoporous silicate comprises silica and optionallyaluminate silicate. The organic linking group L can be a hydrocarbongroup. Alternatively, L can be aromatic group, a fluoroaromatic group,an alkylene group, a fluoroalkylene group, a poly(etherfluoroalkyl)group, or combinations thereof.

The Brönsted acid compound used to surface modify the mesoporoussilicate can include a chemically bonded strong Brönsted acid group.Various methods of modifying the surface of the mesoporous silicate canbe used in embodiments of the present invention. One way of modifyingthe surface of the mesoporous silicate is by adding a phenyl grouphaving a reactive siloxy group, such as phenyl alkoxysilane or phenyltrichlorosilane, to the mesoporous silicate in a solvent and allowinghydrolysis and condensation of the siloxy group to occur, followed bythe addition of a sulfonic acid group on the phenyl linkage to producethe mesoporous catalyst. Alternatively, a vinyl group having a reactivesiloxy group, such as vinyl alkoxysilane or vinyl trichlorosilane, canbe first introduced or added to the mesoporous silicate in a solution,followed by sulfonation to provide the mesoporous catalyst having astructure MP—O—Si—CH₂—CH₂—SO₃H or MP—O—Si—CH(CH₃)—SO₃H. Another way ofpreparing the surface of the mesoporous silicate is by adding a compoundhaving the structure (R′O)₃—Si—R—BA to the mesoporous silicate; oralternatively adding a compound having the structure (R′O)₃—Si—R—CO₂Naor (R′O)₃—Si—R—SO₃Na to the mesoporous silicate followed by acidifyingthe modified surface of the mesoporous silicate to produce themesoporous catalyst having the structure MP—O—Si—R—CO₂H orMP—O—Si—R—SO₃H. In an embodiment, R can be an alkylene, fluoroalkylene,poly(alkylene ether), poly(fluoroalkylene ether), arylene, orfluoroarylene hydrocarbon connecting linkages. Yet another way ofpreparing the surface of the mesoporous silicate is by adding a compoundhaving the following structure to the mesoporous silicate:(R′O)₃Si—CF₂—CF₂—CO₂Na or (R′O)₃Si—CF₂—CF₂—SO₃Na, followed by acidifyingthe compound to produce the mesoporous catalyst having the structureMP—O—Si—CF₂—CF₂—CO₂H or MP—O—Si—CF₂—CF₂—SO₃H. In some embodiments, R′comprises a hydroxy group. In some embodiments, R′ is CH₃, C₂H₅, orC₃H₇.

In some embodiments, the mesoporous silicate has its surface modified bya surface preparation method that includes adding a substance having aBrönsted acid compound or alternatively, a compound that is capable ofbeing converted to a Brönsted acid compound. In some embodiments, themesoporous silicate has its surface modified by a surface preparationmethod selected from the group consisting of phenylsulfonation; additionof triethoxy silyl gamma propyl mercaptan followed by oxidation intosulfonic acid; and addition of a silane of a fluoroalkylenehydrocarboxylate salt, a fluoroarylene carboxylate salt, afluoroalkylene sulfonate salt, or a fluoroarylene sulfonate salt,followed by acidifying the salt back to its acid equivalents. Oxidationcan be performed using peroxide or other methods apparent to those ofskill in the art. Other suitable means for modifying the surface of themesoporous silicate to produce the mesoporous catalyst can be used, willbe apparent to those of ordinary skill in the art, and are to beconsidered within the scope of the present invention.

Once the surface of the mesoporous silicate has been modified by theaddition of the Brönsted acid compound, reactive Brönsted acid sites areavailable for reaction at the surface of the mesoporous catalyst. Thereactive Brönsted acid sites are attached to the mesoporous catalystthrough a stable —Si—O—Si— linkage between the a silicon atom of themesoporous silicate and a silicon atom of the Brönsted acid compound.More than one —Si—O—Si— linkage can form, as described herein.

In embodiments of the present invention, numerous process variables canbe changed without deviating from the scope of the invention. Forexample, isomerizing the NAO can be performed at a temperature of up toabout 300° C. In some embodiments, the temperature is in a range ofabout 65° C. to about 300° C.; alternatively, from about 100° C. toabout 250° C.; or alternatively, from about 150° C. to about 200° C. Inan aspect, the NAO is reacted at a pressure ranging from aboutatmospheric pressure to about 200 atm. In an aspect, the process can bea batch process or a continuous process. Other process variables can bechanged, as will be apparent to those of ordinary skill in the art, andare to be considered within the scope of the present invention.

The NAO can be reacted in the presence of a small amount of a mobilephase acid. Suitable mobile phase acids include propionic acid, methanesulfonic acid, acetic acid, trifluoroacetic acid, toluenesulfonic acid,and combinations thereof. The molar percentage of the mobile acid isabout 1 mol. % to about 10 mol. % of the bonded surface acids. In someembodiments, the mobile acid is used in a range of about 2 mol. % toabout 5 mol. % to adhere on the surface of the mesoporous catalyst andto improve the activity of the mesoporous catalyst without behaving likea homogeneous acid catalyst. Other suitable mobile phase acids will beapparent to those of ordinary skill in the art and are to be consideredwithin the scope of the present invention. A mobile phase acid isoptional, i.e. not required, but can be used.

As another embodiment of the present invention, a process forselectively making a 2-alkene is provided. In this embodiment, a NAOhaving at least 6 carbon atoms is contacted with a mesoporous catalystthat has had its surface modified with a Brönsted acid compoundcomprising a reactive silane connector, an organic linking group, and aBrönsted acid group. The NAO can have at least 6 carbon atoms. The NAOcan have from 6 to 20 carbon atoms; alternatively, from 8 to 20 carbonatoms; alternatively, from 12 to 20 carbon atoms; or alternatively, from6 to 10 carbon atoms. The NAO is then reacted at a temperature of up toabout 300° C. in a reactor to produce a reactor effluent comprising the2-alkene. In an aspect, the reactor effluent comprises at least 35 wt. %2-alkene. In some embodiments, the reactor effluent can comprise atleast 50 wt. % 2-alkene. In other embodiments, it is believed that thereactor effluent comprises at least 25 percent more 2-alkene than thethermodynamic statistical distribution of 2-alkene provides;alternatively, at least 35 percent more 2-alkene than the thermodynamicstatistical distribution of 2-alkene provides; alternatively, at least50 percent more 2-alkene than the thermodynamic statistical distributionof 2-alkene provides. With knowledge of the alpha olefin carbon number,one skilled in the art can readily determine the thermodynamicstatistical distribution of 2-alkene for a particular alpha olefin ormixture of alpha olefins.

As another embodiment of the present invention, a mesoporous catalystfor isomerizing NAO to a composition comprising at least 35 wt. %2-alkene and less than 8 wt. % dimers, branched olefins, or combinationsthereof is provided. In some embodiments, the mesoporous catalystisomerizes the NAO to a composition comprising at least 25 percent more2-alkene than the thermodynamic statistical distribution of 2-alkeneprovides (or any other amount of 2-alkene described herein) and lessthan 8 wt. % dimers, branched olefins, or combinations thereof. In otherembodiments, the composition comprises greater than about 50 wt. %2-alkene. In an aspect, the mesoporous catalyst has a surface that hasbeen modified with a Brönsted acid compound to provide reactive acidsites at the surface of the mesoporous catalyst. The mesoporous catalysthas an average pore diameter in a range of about 12 Å to about 100 Å.

In an aspect, the mesoporous silicate has been modified with theBrönsted acid compound to produce the mesoporous catalyst by a surfacepreparation method selected from the group consisting ofphenylsulfonation; addition of triethoxy gamma propyl mercaptan followedby oxidation into sulfonic acid; and addition of a silane of afluoroalkylenecarboxylate salt, a fluoroarylcarboxylate salt, afluoroalkylene sulfonate salt, or a fluoroarylsulfonate salt, followedby contact with a strong acid. Oxidation can be performed using peroxideor other methods apparent to those of skill in the art. Other methods ofsurface modification will be apparent to those of ordinary skill in theart and are to be considered within the scope of the present invention.

The processes described herein are economical and environmentallyfriendly because the mesoporous catalyst used herein can be easilyrecycled for continuous usage, and, if needed, the mesoporous catalystcan be rejuvenated. If the reactivity of the surface-modified mesoporouscatalyst is reduced, the mesoporous catalyst can be rejuvenated bysurface modifying the mesoporous catalyst again using the methodsdescribed herein. The rejuvenation replenishes the reactive acid siteslocated at the surface of the mesoporous catalyst to increase thereactivity of the mesoporous catalyst. Rejuvenation enables themesoporous catalyst to be used longer, which reduces the amount of newcatalyst that needs to be purchased and the amount of spent catalystthat needs to be discarded.

The resulting 2-alkenes produced using the methods and mesoporouscatalysts described herein can be used in many types of products. Forexample, the 2-alkenes can be used for making products or derivativesfrom oxidation, halogenation, epoxidation, dimerization, andhydroformylation processes. The 2-alkene derivatives can be used indetergents, surfactants, surface activating agents, drilling fluids,lubricants, and the like. Other suitable uses of the 2-alkenes will beapparent to those having ordinary skill in the art and are to beconsidered within the scope of the present invention.

Pre- and Post-Surface Modified Mesoporous Catalyst

In an aspect, in some embodiments, the mesoporous silicate used toproduce the mesoporous catalyst of the present invention is a mesoporousinorganic solid material. The mesoporous silicate comprises silica andcan be in either silicate or aluminate silicate forms. The mesoporoussilicate can be prepared using methods apparent to those of ordinaryskill in the art and are to be considered within the scope of thepresent invention.

The properties used herein to describe the mesoporous catalyst apply tothe pre-surface modification mesoporous silicate and the post-surfacemodification mesoporous catalyst. The properties do not substantiallychange during surface modification of the mesoporous silicate to producethe mesoporous catalyst.

The mesoporous silicate and the mesoporous catalyst can have variousshapes and sizes. In an aspect, for example, the mesoporous silicate andthe mesoporous catalyst have a tubular pore shape.

In an aspect, the mesoporous silicate and the mesoporous catalyst have apore volume in a range of about 0.5 cc/gram to about 2.0 cc/gram.Alternatively, the pore volume can be in a range of about 0.8 to about1.5 cc/gram; or alternatively, from about 1.0 to about 1.25 cc/gram.

In some embodiments, the mesoporous silicate and the mesoporous catalysthave an average pore diameter in a range of about 12 Å to about 100 Å;alternatively, from about 15 Å to about 75 Å; or alternatively, fromabout 20 Å to about 50 Å.

In some embodiments, the mesoporous silicate and the mesoporous catalysthave a surface area of greater than about 400 m²/g. In an aspect, themesoporous silicate and the mesoporous catalyst have a surface area ofbetween about 400 m²/g to about 1400 m²/g; or alternatively, from about500 m²/g to about 1100 m²/g.

The mesoporous silicate and the mesoporous catalyst generally havehoneycombed shaped pores having substantially uniform diameter. Themesoporous silicate and the mesoporous catalyst have an average diameterin a range of about 15 Å to about 70 Å; alternatively, from about 15 Åto about 60 Å; or alternatively, from about 20 Å to about 50 Å.

Brönsted Acid Compound

The Brönsted acid compounds useful in the present invention generallyinclude strong acids, such as sulfonic acids and fluoroalkylcarboxylicacids. In an aspect, the Brönsted acid compound comprises a reactivesilane connector, an organic linking group, and a Brönsted acid group.In some embodiments, the reactive silane connector and the organiclinking group can be introduced sequentially. In some embodiments, theorganic linking group and the Brönsted acid group can be introduced atthe same time in one compound.

In some embodiments, the Brönsted acid compound has a formula asfollows:

X₃—Si—R—SO₃H,

wherein X comprises a halogen or an alkoxy group and R comprisesaromatic group, a fluoroaromatic group, an alkylene group, afluoroalkylene group, a poly(etherfluoroalkyl) group, or combinationsthereof. One skilled in the art will recognize that the silicon atom inthe above structure has two undesignated valencies. As used herein, theundesignated silicon valencies can each independently be X, a linkinggroup having a Brönsted acid group, or any other group attached to thesilicon atom (e.g. a hydrocarbon group not having a Brönsted acidgroup). When this type of Brönsted acid compound is used, X₃—Si is thereactive silane connector, R is the organic linking group, and SO₃H isthe Brönsted acid group. X can be Cl, Br, or OR′, with R′ being CH₃,C₂H₅, or C₃H₇. R can be —(CH₂)_(x)—, —C₆H₄—, —(CF₂—CF₂)_(x)—,—(CF₂—CF₂)_(x)—O—(CF₂—CF₂)_(y)—, or —C₆F₄—.

In some embodiments, the Brönsted acid compound has a formula asfollows:

X₃—Si—FR—COOH,

wherein X comprises a halogen or an alkoxy group and FR comprisesaromatic group, a fluoroaromatic group, an alkylene group, afluoroalkylene group, a poly(etherfluoroalkyl) group, or combinationsthereof. One skilled in the art will recognize that the silicon atom inthe above structure has two undesignated valencies. As used herein, theundesignated silicon valencies can each independently be X, a FR linkinggroup having a Brönsted acid group, or any other group attached to thesilicon atom (e.g. a hydrocarbon group not having a Brönsted acidgroup). When this type of Brönsted acid compound is used, X₃—Si is thereactive silane connector, FR is the organic linking group, and COOH isthe Brönsted acid group. X can be Cl, Br, or OR′, with R′ being CH₃,C₂H₅, or C₃H₇. FR can be —(CH₂)_(x)—, —C₆H₄—, —(CF₂—CF₂)_(x)—,—(CF₂—CF₂)_(x)—O—(CF₂—CF₂)_(y)—, or —C₆F₄—.

Other suitable Brönsted acid compounds will be apparent to those ofordinary skill in the art and are to be considered within the scope ofthe present invention.

Reactive Silane Connector

The reactive silane connector can comprise between one and twenty carbonatoms. The reactive silane connector contains a silicon atom and atleast one leaving group attached to the silicon atom that connects theBrönsted acid compound to the mesoporous silicate to produce themesoporous catalyst. The reactive silane connector can include compoundsthat are capable of forming at least one stable MP—O—Si linkage; oralternatively, between one and three MP—O—Si linkages. Upon reactionwith the mesoporous catalyst, the —Si atom in the reactive silaneconnector becomes attached to the SiOH group in the mesoporous silicateto form at least one of the MP—O—Si linkages.

The reactive silane connector can comprise a halosilane group or analkoxysilane group. The halosilane group minimally has at least onehalogen silicon bond; or alternatively, from 1 to 3 halogen siliconbonds. In an embodiment, the halosilane can have the general formula ofX₃—Si—, wherein X is chlorine, bromine, or an alkoxy group. Thealkoxysilane group minimally has at least one alkoxy silicon bond; oralternatively, from 1 to 3 alkoxy silicon bonds. In an embodiment, thealkoxysilane can have the general formula of (R′O)₃—Si—, wherein R′ canbe any hydrocarbon group. Suitable alkoxy groups can include methoxy,ethoxy, or propoxy. Other suitable silane connecting groups will beapparent to those of ordinary skill in the art and are to be consideredwithin the scope of the present invention.

Organic Linking Group

As used herein, an “organic linking group” is defined as an organicsubstituent group, regardless of functional type, having the requiredfree valencies at one or more carbon atom(s) to link the indicatedelements. Thus, an organic linking group can contain organic functionalgroup(s) and/or atom(s) other than carbon and hydrogen (i.e. an organiclinking group that can comprise functional groups and/or atoms inaddition to carbon and hydrogen). For example, non-limiting examples ofatoms other than carbon and hydrogen include halogens, oxygen, nitrogen,and phosphorus, among others. Non-limiting examples of functional groupsinclude ethers, sulfides, amines, and phosphines, among others. Includedin the organic linking group definition are heteroatom containing rings,heteroatom containing ring systems, heteroaromatic rings, andheteroaromatic ring systems. Finally, it should be noted that theorganic linking group definition includes the organic linking groupconsisting of inert functional groups, and the hydrocarbon linking groupas members. Similarly, an “organylene group” refers to an organicsubstituent group, regardless of functional type, formed by removing twohydrogen atoms from one or two carbon atoms of an organic compound andan “organic linking group” refers to a generalized organic substituentgroup formed by removing one or more hydrogen atoms from one or morecarbon atoms of an organic compound.

As used herein, an “alkylene group” is defined as a univalent groupformed by removing two hydrogen atoms from a hydrocarbon (i.e. a groupcontaining only carbon and hydrogen). An alkylene group can include theterm “alkylene” or “hydrocarbylene group.” An alkylene group can includerings, ring systems, aromatic rings, and aromatic ring systems thatcontain only carbon and hydrogen.

In an aspect, the organic linking group can be aromatic group, afluoroaromatic group, an alkylene group, a fluoroalkylene group, apoly(etherfluoroalkyl) group, or combinations thereof. When the Brönstedacid group contains a sulfonic acid group, the organic linking groupgenerally comprises an alkylene group or an aromatic group. When theBrönsted acid group contains a carboxylic acid group, the organiclinking group generally comprises a fluoroalkylene group or afluoroaromatic group.

In some aspects, when the organic linking group comprises the alkylenegroup, the alkylene group comprises one to ten carbon atoms; oralternatively, one to five carbon atoms. The alkylene group can be amethylene group, an ethylene group, or a propylene group.

In some embodiments, the organic linking group has the followingformula: —(CH₂)_(x)—, wherein x is in a range of one to ten.Alternatively, x can range from one to five.

The organic linking group can be an aromatic group or a fluoroaromaticgroup. When the organic linking group comprises the aromatic group, theorganic linking group has the following formula: —C₆H₄—. When theorganic linking group comprises the fluoroaromatic group, the organiclinking group has the following formula: —C₆F₄—, such astetrafluorobenzene.

The organic linking group can comprise a fluoroalkane group or afluoroaromatic group. When the organic linking group comprises thefluoroalkane group, the fluoroalkane group generally has the followingformula: —(CF₂—CF₂)x-.

Other suitable organic linking groups will be apparent to those ofordinary skill in the art and are to be considered within the scope ofthe present invention.

Brönsted Acid Group

In an aspect, the Brönsted acid group is a sulfonic acid group or acarboxylic acid group. In an aspect, the Brönsted acid group comprises asulfonic acid group. In an aspect, the Brönsted acid group comprises acarboxylic acid group.

In some aspects, the sulfonic acid group has the general formula of—SO₃H. In some aspects, the carboxylic acid group has the generalformula of —COOH.

Other suitable Brönsted acid groups will be apparent to those ofordinary skill in the art and are to be considered within the scope ofthe present invention.

Combined Reactive Silane Connector and Organic Linking Group

Suitable compounds that can be reacted with the mesoporous silicate toform the mesoporous catalyst following subsequent reactions, asdescribed herein, can include phenyltrichlorosilane,phenyltriethoxysilane, phenyltrimethoxysilane, vinyltriethoxysilane,vinyltrimethoxysilane, trichlorovinylsilane, allyltrichlorosilane, orcombinations thereof. Other suitable combined silane connecting andorganic linking groups will be apparent to those of ordinary skill inthe art and are to be considered within the scope of the presentinvention.

EXAMPLES Phenylation of Silicate Having Mesoporous Pore Diameters

50 grams of a mesoporous silicate having mesoporous pore diameters wasstirred into 250 cc of a 4:1 ethanol:water mixture, along with 10 dropsof acetic acid or propionic acid as an acid hydrolysis catalyst. Asufficient amount of phenyl silane (MW 240) to provide a monolayercoating on the surface of the silicate was added while being vigorouslystirred at 60-80° C. overnight.

The amount of phenyl silane was doubled and quadrupled to see ifadditional layers would provide higher amounts of surface phenyl groups.The additional amounts of phenyl silane resulted in higher amounts ofsurface phenyl groups. The amount of surface phenyl groups wasdetermined later by titration after the surface of the silicate had beensulfonated. Phenyl sulfonated pores of silicate with 0.05 to 0.81 mmoles acid per gram of silicate were produced.

Sulfonation of Phenyl Silicate

The silicate structures were dried to constant weight under vacuum toavoid allowing the moisture to dilute and weaken the SO₃, which canresult in a lower degree of sulfonation. The sulfonation of the phenylgroups attached on the silicate was completed by adding 50 wt. % excessfuming sulfuric acid (containing 18 to 30 wt. % SO₃) into 50 grams ofvacuum dried phenyl silicate in 300 cc methylene chloride while vigorousstirring at 35° C. for 4 hours. The molar equivalent acids on thesurface were determined by acid-base titration.

Because trialkoxy silane is trifunctional and could polymerize on thesilica surface to produce a crosslinked multilayer coating instead of amonolayer coating, the surface was silylated with an excessive monofunctional silane, phenyldimethyl chlorosilane, which provides onlysingle bonding to the silica surface to check the active silanol siteson the solid surface. Using the mono functional silane produced 0.1 mmole/g of acid after sulfonation, which is the molar equivalent ofsilanol Si—OH density on the surface. Any loading of phenyl groupssignificantly above that was due to the crosslinking of thetrifunctional phenyl silane to form a multilayer coating thicker thanthe monolayer coating on the mesoporous catalyst surface. The excessacid functionality could be measured by acid base titrations to show ahigher acid concentration. The results can be found in Table 1.

TABLE 1 Theoretical Sulfonated Titration Data Sample No. Phenylsilane, mMole Molar Equivalents Acid 1 0.34 0.430 2 0.50 0.041 3 0.25 0.033 40.25 0.051 5 0.25 0.033 6 0.25 0.101 7 0.50 0.117 8 0.75 0.140 9 0.250.164 10 0.50 0.230 11 0.75 0.809 12 Excess dimethylchlorophenyl 0.106silane 13 0.50 0.037 14 0.50 0.247 15 0.50 0.272 16 0.227 17 0.090

While the compositions and methods of this invention have been describedin terms of particular embodiments, it will be apparent to those ofordinary skill in the art that variations can be applied to thecompositions and methods and in the steps or in the sequence of steps ofthe methods described herein without departing from the concept, spiritand scope of the invention. For example, it will be apparent thatcertain agents that are chemically related can be substituted for theagents described herein while the same or similar results would beachieved. All such similar substitutes and modifications apparent tothose skilled in the art are deemed to be within the spirit, scope andconcept of the invention as defined by the appended claims.

1. A process for making a 2-alkene, comprising the steps of: contactinga NAO having at least 6 carbon atoms and a mesoporous catalyst that hasbeen surface modified with a substance comprising a Brönsted acidcompound; and isomerizing the NAO in a reactor to produce a reactoreffluent comprising the 2-alkene.
 2. The process of claim 1, wherein theBrönsted acid compound has been grafted onto a surface of the mesoporouscatalyst, the Brönsted acid compound comprising a reactive silaneconnector, an organic linking group, and a Brönsted acid group.
 3. Theprocess of claim 1, wherein the Brönsted acid compound comprises areactive silane connector comprising a halosilane group, an alkoxysilanegroup, or combinations thereof.
 4. The process of claim 1, wherein theBrönsted acid compound comprises an organic linking group comprising anaromatic group, a fluoroaromatic group, an alkylene group, afluoroalkylene group, a poly(etherfluoroalkyl) group, or combinationsthereof.
 5. The process of claim 1, wherein the Brönsted acid compoundcomprises a Brönsted acid group comprising a sulfonic acid group, acarboxylic acid group, or combinations thereof.
 6. The process of claim1, wherein the Brönsted acid compound has a formula as follows:X₃—Si—R—SO₃H, wherein X comprises a halogen, an alkoxy group, orcombinations thereof and R comprises aromatic group, a fluoroaromaticgroup, an alkylene group, a fluoroalkylene group, apoly(etherfluoroalkyl) group, or combinations thereof.
 7. The process ofclaim 1, wherein the Brönsted acid compound has a formula as follows:X₃—Si—FR—COOH, wherein X comprises a halogen or an alkoxy group and FRcomprises aromatic group, a fluoroaromatic group, an alkylene group, afluoroalkylene group, a poly(etherfluoroalkyl) group, or combinationsthereof.
 8. The process of claim 1, wherein the reactor effluentcomprises at least 35 wt. % 2-alkene and less than about 8 wt. % olefindimers or branched olefins.
 9. The process of claim 1, wherein thereactor effluent comprises at least 25% more 2-alkene that athermodynamic statistical distribution of 2-alkenes provides.
 10. Theprocess of claim 1, wherein the mesoporous catalyst has an average porediameter ranging from about 12 Å to about 100 Å.
 11. The process ofclaim 1, wherein the mesoporous catalyst has a surface area ranging fromabout 400 m²/g to about 1400 m²/g.
 12. The process of claim 1, whereinthe mesoporous catalyst has a pore volume ranging from about 0.5 cc/g toabout 2.0 cc/g.
 13. The process of claim 1, wherein the step ofisomerizing the NAO is performed in a presence of a mobile phase acid.14. A process for making a 2-alkene, comprising: contacting a NAO havingat least 6 carbon atoms and a mesoporous catalyst that is surfacemodified with a Brönsted acid compound comprising a reactive silaneconnector, an organic linking group, and a Brönsted acid group, themesoporous catalyst having an average pore diameter ranging from about12 Å to about 100 Å and having a pore volume ranging from about 0.5 cc/gto about 2.0 cc/g; and isomerizing the NAO at a temperature of up toabout 300° C. in a reactor to produce a reactor effluent comprising atleast 35 wt. % 2-alkene.
 15. The process of claim 14, wherein thereactive silane connector comprises a halosilane group, an alkoxysilanegroup, or combinations thereof.
 16. The process of claim 14, wherein theorganic linking group comprises an aromatic group, a fluoroaromaticgroup, an alkylene group, a fluoroalkylene group, apoly(etherfluoroalkyl) group, or combinations thereof.
 17. The processof claim 14, wherein the Brönsted acid group comprises a sulfonic acidgroup, a carboxylic acid group, or combinations thereof.
 18. The processof claim 14, wherein the mesoporous catalyst has a surface area betweenabout 400 m²/g to about 1400 m²/g.
 19. The process of claim 14, whereinthe step of isomerizing the NAO is performed in a presence of a mobilephase acid.
 20. A modified mesoporous catalyst having a surface that hasbeen modified with a substance comprising a Brönsted acid group toprovide reactive acid sites at the surface of the modified mesoporouscatalyst, the modified mesoporous catalyst having an average porediameter in a range of about 12 Å to about 100 Å, the modifiedmesoporous catalyst having a structure as follows:MP—O—Si-L-BA, wherein MP comprises a mesoporous silicate, L comprises anorganic linking group, and BA comprises the Brönsted acid group.
 21. Themodified mesoporous catalyst of claim 20, wherein the organic linkinggroup comprises an aromatic group, a fluoroaromatic group, an alkylenegroup, a fluoroalkylene group, a poly(etherfluoroalkyl) group, orcombinations thereof and the Brönsted acid group comprises a carboxylicacid group, a sulfonic acid group, or combinations thereof.
 22. Themodified mesoporous catalyst of claim 20, wherein the modifiedmesoporous catalyst has been modified with the Brönsted acid compound bya surface modification method selected from the group consisting ofphenylsulfonation, addition of triethoxy gamma propyl mercaptan followedby oxidation, and addition of a silane of a fluoroalkylene carboxylatesalt, a fluoroarylene carboxylate salt, a fluoroalkylene sulfonate salt,or a fluoroarylene sulfonate salt followed by contacting a strong acid.23. The modified mesoporous catalyst of claim 20 having a surface arearanging from about 400 m²/g to about 1400 m²/g, a pore volume rangingfrom about 0.5 cc/gram to about 2.0 cc/gram, and a maximum operatingtemperature of up to about 300° C.